首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   229464篇
  免费   13127篇
  国内免费   6851篇
耳鼻咽喉   2774篇
儿科学   8369篇
妇产科学   3035篇
基础医学   16804篇
口腔科学   4266篇
临床医学   28153篇
内科学   40188篇
皮肤病学   3112篇
神经病学   11223篇
特种医学   12953篇
外国民族医学   27篇
外科学   33603篇
综合类   22089篇
现状与发展   26篇
一般理论   3篇
预防医学   14930篇
眼科学   4684篇
药学   25479篇
  112篇
中国医学   5311篇
肿瘤学   12301篇
  2023年   2100篇
  2022年   3850篇
  2021年   9258篇
  2020年   5614篇
  2019年   11393篇
  2018年   6003篇
  2017年   5310篇
  2016年   7324篇
  2015年   10248篇
  2014年   18349篇
  2013年   16343篇
  2012年   19428篇
  2011年   16273篇
  2010年   15032篇
  2009年   14471篇
  2008年   12989篇
  2007年   13182篇
  2006年   11166篇
  2005年   7475篇
  2004年   3880篇
  2003年   3347篇
  2002年   2740篇
  2001年   2265篇
  2000年   2017篇
  1999年   1264篇
  1998年   1653篇
  1997年   1447篇
  1996年   1210篇
  1995年   1264篇
  1994年   1221篇
  1993年   969篇
  1992年   1181篇
  1991年   1100篇
  1990年   1087篇
  1989年   1038篇
  1988年   960篇
  1987年   834篇
  1986年   694篇
  1985年   1595篇
  1984年   1754篇
  1983年   1264篇
  1982年   1343篇
  1981年   1329篇
  1980年   1147篇
  1979年   991篇
  1978年   759篇
  1977年   758篇
  1976年   661篇
  1974年   456篇
  1973年   432篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
75.
《Vaccine》2022,40(24):3320-3329
BackgroundCurrently, booster dose is needed after 2 doses of non-live COVID-19 vaccine. With limited resources and shortage of COVID-19 vaccines, intradermal(ID) administration might be a potential dose-sparing strategy.ObjectiveTo determine immunologic response and reactogenicity of ID ChAdOx1 nCoV-19 vaccine (AZD1222,Oxford/AstraZeneca) as a booster dose after completion of 2-dose CoronaVac(SV) in healthy adult.MethodsThis is a prospective cohort study of adult aged 18–59 years who received 2-dose SV at 14–35 days apart for more than 2 months. Participants received ID AZD1222 at fractional low dose(1×1010 viral particles,0.1 ml). Antibody responses were evaluated by surrogate virus neutralization test(sVNT) against delta variant and wild type, and anti-spike-receptor-binding-domain immunoglobulin G(anti-S-RBD IgG) at prior, day14, 28, 90, and 180 post booster. Solicited reactogenicity was collected for 7 days post-booster. Primary endpoint was the differences of sVNT against delta strain ≥ 80% inhibition at day14 and 90 compared with the parallel cohort study of 0.5-ml intramuscular(IM) route.ResultsFrom August2021, 100 adults with median age of 46 years(IQR 41–52) participated. Prior to booster, geometric mean(GM) of sVNT against delta strain was 22.4% inhibition(95 %CI 18.7–26.9) and of anti-S-RBD IgG was 109.3 BAU/ml(95.4–125.1). Post ID booster, GMs of sVNT against delta strain were 95.5% inhibition (95%CI 94.2–96.8) at day14, 73.1% inhibition (66.7–80.2) at day90, and 22.7% inhibition (14.9–34.6) at day180. The differences of proportion of participants achieving sVNT against delta strain ≥ 80% inhibition in ID recipients versus IM were + 4.2% (95 %CI -2.0to10.5) at day14, and ?37.3%(-54.2to-20.3) at day90. Anti-S-RBD IgG GMs were 2037.1 BAU/ml (95%CI 1770.9–2343.2) at day14 and 744.6 BAU/ml(650.1–852.9) at day90, respectively. Geometric mean ratios(GMRs) of anti-S-RBD IgG were 0.99(0.83–1.20) at day14, and 0.82(0.66–1.02) at day90. Only 18% reported feverish, compared with 37% of IM (p = 0.003). Common reactogenicity was erythema at injection site(53%) while 7% reported blister.ConclusionLow-dose ID AZD1222 booster enhanced lower neutralizing antibodies at 3 months compared with IM route. Less systemic reactogenicity occurred, but higher local reactogenicity.  相似文献   
76.
PurposeThe albumin-bilirubin (ALBI) grade has been established as an improved predictor of survival in patients with hepatocellular carcinoma (HCC) treated with conventional transarterial chemoembolization and yttrium-90 radioembolization. The purpose of the study was to investigate the utility of ALBI grade in prognosticating outcomes in patients with HCC treated with drug-eluting embolic (DEE) transarterial chemoembolization (TACE).Materials and MethodsA single-center retrospective review was performed to compare the efficacy of ALBI grade and Child-Pugh (CP) classification in predicting the survival of patients with HCC receiving DEE-TACE. A total of 303 patients with HCC were identified who had received DEE-TACE without concomitant locoregional therapy within 30 days. Survival analysis was performed using Kaplan-Meier methods and censored for curative therapy. Survival curves were stratified based on the ALBI grade, CP class, Barcelona Clinic Liver Cancer (BCLC) stage, Eastern Cooperative Oncology Group performance status, and presence of ascites. The discriminatory ability of survival curves was calculated by C-Index.ResultsKaplan-Meier survival curves stratified by the ALBI grade produced distinct, nonoverlapping curves (P < .001), showing greater discriminatory ability than the CP classification (C-index = 0.568 and 0.545, respectively). The substratification of the BCLC stage by the ALBI grade yielded greater discriminatory ability than the substratification by the CP classification (C-index = 0.573 and 0.565, respectively). For patients with BCLC stage B, the substratification by the ALBI grade yielded distinct curves, whereas the substratification by the CP classification did not (P = .011 and P = .379, respectively).ConclusionsALBI grade showed improved discriminatory ability compared with CP classification in differentiating overall survival among patients with HCC receiving DEE-TACE. Furthermore, ALBI grade was effective in substratifying survival among patients categorized as CP class A and patients with BCLC stage B, whereas CP classification was not effective.  相似文献   
77.
BackgroundWe assessed whether or not covalently closed circular DNA (cccDNA) levels in the background liver influence the recurrence of hepatocellular carcinoma (HCC) in patients with resolved hepatitis B virus (HBV) infection.MethodsAmong 425 patients who underwent initial hepatectomy for HCC between 2010 and 2018, a retrospective review was performed in 44 with resolved HBV infection. The clinicopathologic characteristics were analyzed for correlation with tumor recurrence. The HBV cccDNA levels were tested via a droplet digital polymerase chain reaction assay.ResultsHBV cccDNA was detected in 27 of 44 patients (61%), and the median level was 1.0 copies/1000 ng (range, 0-931.3 copies/1000 ng). Anti-HBc ≥8.9 S/CO was associated with cccDNA detection (odds ratio, 11.08; 95% confidence interval [95% CI], 2.48-49.46; P = 0.002). Twenty-eight patients (64%) developed HCC recurrence after hepatectomy. The overall 3- and 5-year recurrence-free survival rates were 45.7% and 34.3%, respectively.19 HBV cccDNA levels was not significantly associated with HCC recurrence, while the presence of multiple tumors was an independent risk fact or (hazard ratio, 6.53; 95% CI, 2.48-17.19; P < 0.001.ConclusionHBV cccDNA levels did not influence HCC recurrence after hepatectomy. Anti-HBc levels may be used as a surrogate marker for cccDNA.  相似文献   
78.
79.
《Vaccine》2022,40(41):5997-6000
Coronavirus disease 2019 (COVID-19) vaccine administration started in February 2021 in Japan. As of December 2021, approximately 75% of the population aged ≥12 years had received two doses of vaccine. We conducted a study to investigate vasovagal reactions (VVR) after COVID-19 vaccination using data on adverse events following immunization. The crude reporting rate of VVR (cases/1,000,000 doses) after vaccination was 9.6 in all age groups combined, and was more frequent in the younger age groups: 28.6 and 37.2 in individuals aged 10–19 years and 20–29 years, respectively. In individuals aged 10–29 years, the rate was similar in males and females (33.0 and 34.2, respectively, p = 0.53); but was higher after dose 1 than after dose 2 (57.4 and 8.8, respectively, p < 0.001). Based on these results, caution needs to be exercised when vaccinating adolescents and young adults, especially with dose 1 of COVID-19 vaccines.  相似文献   
80.
PurposeTo compare the technical success of antegrade uteral stent (AUS) and retrograde ureteral stent (RUS) placements in patients with malignant ureteral obstruction (MUO) and to determine the predictors of technical failure of RUS.Materials and MethodsThis study retrospectively included 61 AUS placements (44 patients) performed under fluoroscopic guidance and 76 RUS placements (55 patients) performed under cystoscopic guidance in patients with MUO from January 2019 to December 2020. Technical success rates of the 2 techniques were compared using inverse probability of treatment weighting (IPTW) analysis. Logistic regression was used to identify predictive factors for technical failures.ResultsTechnical success was achieved in 98.4% of the AUS group and 47.4% of the RUS group. After stabilized IPTW, the technical success rate was higher in the AUS group than in the RUS group (adjusted risk difference, 49.4%; 95% confidence interval [CI], 35.4%–63.1%). The independent predictors for technical failure of the RUS procedure were age of ≥65 years (odds ratio [OR], 5.56; 95% CI, 1.73–21.27), ureteral orifice invasion (OR, 4.21; 95% CI, 1.46–13.46), and extrinsic cancer (OR, 15.58; 95% CI, 2.92–111.81).ConclusionsThe technical success rate of AUS placement was higher than that of RUS placement in patients with MUO. RUS failure was associated with age of ≥65 years, cancer with ureteral orifice invasion, and extrinsic ureteral obstruction.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号